A nation-wide medical record database study: Value of hepatitisB surface antigen loss in chronic hepatitisB patients in Japan.

Abstract

HepatitisB surface antigen (HBsAg) seroclearance is considered to be one of the best surrogate endpoints of functional cure for hepatitisB virus (HBV) infection. However, evidence regarding the relationship between achieving HBsAg seroclearance or a low baseline HBsAg level, and long-term clinical outcomes in Japanese patients with chronic HBV infection remains to be confirmed in a real-world setting. A retrospective observational cohort study was performed with an electronic medical record database, including data from 230 hospitals across Japan. Chronic HBV infection was defined as two consecutive, positive HBsAg laboratory measurements for HBV infection. The date of the second positive was used as a baseline to identify subsequent HBsAg seroclearance and liver disease progression. In the database, 2523 patients with chronic HBV infection were identified as the chronic hepatitisB (CHB) cohort. Among the CHB cohort with an average observational period of 5.19±3.87years, 202 patients (8%) achieved HBsAg seroclearance after baseline. They had a lower risk of developing hepatocellular carcinoma (HCC) (adjusted hazard ratio [aHR] 0.206, p<0.01) and cirrhosis (aHR 0.361, p<0.01). When the CHB cohort was stratified into two groups based on baseline HBsAg levels (<100IU/mL and ≥100IU/mL), patients with a lower baseline level of HBsAg (<100IU/mL) had a lower risk of developing liver disease (HCC aHR 0.600, p<0.01; cirrhosis aHR 0.618, p<0.05). These results confirm the clinical significance of HBsAg seroclearance and low HBsAg level at baseline with respect to long-term outcomes of patients with CHB in the Japanese population.